1. Field of the Invention
The present invention relates to improvements in web cam buckles such as are used in motorcycle transport tie-down restraints. The improvements herein described provide cam buckle tie-down with higher pre-load capacities. Also included are improvements in the design of associated web hooks for the tie-downs.
2. Background Art
The huge outdoor recreation industry in the United States has resulted in a requirement for transporting motorcycles and other RV vehicles.
Within this backdrop, the inventor hereof has devised several mechanisms that in one way or another assist in lifting and transporting a recreational device like a motorcycle or a personal watercraft as exemplified in the teachings of U.S. Pat. Nos. 4,790,713 and 4,932,829 that were issued to the inventor hereof, and in published U.S. Patent Application Publication No. 2005/0111945 also to the present inventor.
More recently there are described even further improvements in lifting mechanisms such as those disclosed in U.S. patent application Ser. No. 12/321,267 filed Sep. 2, 2008 for a truck bed carrier and U.S. patent application Ser. No. 12/384,630 filed Apr. 8, 2009 dealing with the confined lifting geometries associated with an enclosed carrying vehicle, both of which are incorporated by reference as if fully set out at length herein.
It is well appreciated that any extended transport of RV vehicles will require proper restraint of that cargo during transport.
The principal components in the restraint methods, are the wheel chocks to restrain horizontal movement, and the adjustable tie-down straps or cables used to limit vertical movement of the cargo. These tie-down restraints have two load requirements: Maximum Working Load—this is the strength of mechanical components of the tie-down assembly reduced by a safety factor. Preload—Is the static down force imposed on the transported vehicle by tie-downs. The preload tension desired will depend primarily on the weight of the restrained vehicle and the stiffness of the suspension system of said vehicle. The purpose of “preload” is to obtain sufficient down-force on the suspension to limit vertical movement of a vehicle during transport, but to not apply excess preload force which can damage the vehicle suspension system.
In the past years, simple cam buckle tie-downs have worked well for restraining lighter weight motorcycles. The simple cam buckle tie-downs are limited in the amount of preload force to what one normal person can pull. For that reason the preferred tie-down for heavy motorcycles has been the ratchet type where the higher restraining forces are obtained by winding up a flexible strap onto a ratcheted spool, as exemplified in the teachings of U.S. Pat. No. 7,416,167 issued to Knox, U.S. Pat. No. 6,547,218 issued to Landy, and many others. These ratchet type mechanisms are unwieldy in the cramped spaces of the cargo area of trucks and trailers. The light duty ratchets can only wind up a short amount of web material on the small spools: which results in lengthy adjustment time. Also when the high compression force in the transported vehicle's suspension system is released by the ratchet pawl, there can be a dangerous jump movement in the transported vehicle.
For these reasons, the convenience of a flexible strap with a cam buckle is often preferred over ratcheted types. However, the simple cam buckles are limited in the amount of preload force that can be imposed by one's arm in a cramped space. For that reason a cam buckle that developed additional force due to multiplication by internal pulleys would be a welcome solution to many recreational vehicle tie-down requirements.
The clamping buckles that are particularly adapted for these tie-down applications are cam buckles including a one Piece frame exemplified by buckles sold under model designations 40880-22; 42195-11; or 40880-15 by Ancra International, LLC, Hawthorne, Calif. Cam buckles of this type typically include a generally C-sectioned unitary frame supporting a pivot extending between the lateral walls thereof on which a spring biased lever is pivoted to press a toothed cam against a strap or belt extending through the frame interior. Once grasped against the strap tension, the engagement of the cam is then released only by pressing the lever against its spring bias, thereby lifting the cam from its captured position against the strap.
It has been found that in the foregoing cam buckle structure the lateral walls of the single piece frame can be rendered even more useful to serve as supports for additional pivots about which the strap can be looped in order to obtain the load multiples of additional pulleys. Also by proper location of the primary pulley and the locking cam, the load strap is directed just under the actuating lever of the cam, so that tension in the web will provide a lifting force to the lever to initiate rotational closing of the web clamp. The shape of the clamp cam with directed teeth, then locks the load strap and prevents its release unless direct pressure is applied to actuating lever. This eliminates the need for an actuating spring.
Typical motorcycle tie-downs have heavy steel “S” open hooks at the ends to allow attachment between motorcycle and vehicle carrier. For modern motorcycles, the steel hooks (even with vinyl coatings), are not acceptable to the vehicle owner. For this reason, “soft hooks” are used for direct attachment to the cycle. These soft hooks are stitched nylon web loops that can be cinched to suitable motorcycle structure with a length adequate to keep the heavy hook and the adjacent steel web clamp a safe distance from the motorcycle during transport. The open hooks are trapped onto the restrained vehicle by the web tension. However, certain rough road conditions (dips, heaves, ruts, etc.) and sudden carrier vehicle direction changes can create so much movement on the motorcycle suspension as to allow the standard open hooks to escape from the soft hook web loop. A new web clamp design that incorporated a hook in the design of the web clamp frame was described in the parent application hereof. This integral hook is described as having a closing latch to support the open side of hook, and of course the latch prevents the possibility of the hook escaping the loop of a soft hook.
Since “soft hooks” are a standard means to attach to street motorcycles, there is a need for optimum means to attach to these types of web loops. An alternate design specific for a web hook that will lend itself for use as web clamp end-attachment is also described herein.
The web clamp designs herein resulted in another consideration for motorcycle tiedown equipment. When motorcycles are transported inside trailers or trucks, the web clamps are frequently in a location that is access restricted. In this case, the direction orientation of the web clamp is critical in order to allow the operator to have a straight line pull on the web tensioning end of a tie-down. Also with the inventive force multiplying web clamp design, it is important to avoid misaligned or twisted webs on the tie-down, as the increased friction will limit the ability for the web clamp to develop the desired web tension. It is the accommodation of the new web clamp design that will insure optimum orientation of the web clamp for the operator, and proper alignment of the web with the web clamp. As used herein, the terms “web and “strap” are interchangeable.